refactor: Rework CSS and move toward a theme system more like shadcn, some optimizations

[adoyle0]

• Theme::Default is renamed to Theme::Neutral and the default theme is now Theme::Neutral
• Alert now grows to the full width of its container
• Added AlertAction component
• as_button Link prop renamed to render_as and now takes a String. as_button=true is now render_as="button"
• Links can now render as Badges with render_as="badge"
• Added size prop to Avatar
• Added AvatarBadge and AvatarGroupCount
• Added "none" variant to Button
• Added BreadcrumbEllipsis, BreadcrumbList, BreadcrumbPage
• Breadcrumb changed name to BreadcrumbList and was replaced with a nav container component
• Breadcrumb component is a bit more accessible with some aria roles and tags for screen readers
• SelectItem renamed to SelectOption
• SelectContent renamed to SelectOptGroup
• Added basic multi-select support (select multiple not working #52) (TODO: reactive value)
• Added CardAction
• ContextMenuTrigger, DialogTrigger, DropdownMenuTrigger, and PopoverTrigger are now Trigger and DialogTrigger is no longer a slot
• ContextMenuContent and DropdownMenuContent are now MenuContent
• ContextMenuGroup and DropdownMenuGroup are now MenuGroup
• ContextMenuLabel, DropdownMenuLabel, and FieldLabel are now combined with Label
• ContextMenuItem and DropdownMenuItem are now MenuItem
• ContextMenuShortcut and DropdownMenuShortcut are now MenuShortcut
• ContextMenuSub and DropdownMenuSub are now MenuSub
• ContextMenuSubTrigger and DropdownMenuSubTrigger are now MenuSubTrigger
• ContextMenuSubContent and DropdownMenuSubContent are now MenuSubContent
• ButtonGroupSeparator, ContextMenuSeparator, DropdownMenuSeparator, FieldSeparator, and ItemSeparator are now combined with Separator
• <Dialog alert=true> is now <AlertDialog>
• Added DialogCancel and DialogAction
• Added DialogMedia for AlertDialog
• Added DialogContent which is now required
• AspectRatio ratio now takes a String
• Progress max and value props now take f64